Gain compensating method for flaw detector

Abstract

The gain compensating method for flaw detector is to control the voltage of the voltage control end of the program controlled amplifier with one device containing CPU module, programmable logic device and D / A converter so as to realize the gain compensation. The method includes the following steps: 1. to set the time parameters of the channels and corresponding gain parameters; 2. for the control panel to transmit channel signal to the CPU module; 3. for the CPU module to transmit corresponding channel parameter to the programmable logic device for starting; 4. for the programmable logic device to time and compare the time value with the time parameters of the channels; 5. to output the gain data of the channel with time parameter equal to the timed value to the D / A converter; and 6. for the D / A converter to convert the gain data into a control voltage transmitted to the programmed amplifier before returning to step 4.

Description

technical field [0001] The invention relates to a gain compensation method of a flaw detector. Background technique [0002] In the application of ultrasonic flaw detection, after the ultrasonic wave is emitted by the transducer, the sound wave gradually attenuates when it propagates in the workpiece to be tested. Therefore, if there is a defect in the workpiece to be tested, the sound intensity of the sound wave reflection decreases with the increase of the depth of the defect. In order to make deep defects more obvious, in some applications, the gain of the ultrasonic receiving amplifier is usually designed to increase with the increase of depth (ie time), that is, depth compensation. Amplifiers that can achieve deep compensation are also called program-controlled amplifiers, namely Amp. Most of them have been made into integrated circuits. Its amplification varies with the voltage of the voltage control terminal, and its gain (dB) is almost linear with the control voltage...

AI Technical Summary

Problems solved by technology

[0005] 1. The gain can only be controlled according to the same curve rule, that is, there are only two stages of gain. If you want to emphasize the gain of a certain depth range, the circuit will be much more complicated, difficult to implement, and the cost is also high

[0006] 2. If there are multiple probes, each probe is a channel, and each channel has its own control requirements, the circuit becomes more complicated and requires many potentiometers, further increasing the cost of the circuit

[0007] 3. In the actual use process, due to the difficulty of adjusting the potentiometer and other components, it is impossible to modify the parameters at any time, so it cannot meet the needs of use

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